Cover plate for measuring instruments



1929! Le. TINGLEY 1,723,390

COVER PLATE FOR MEASURINGIINYSTRUMEN'KS Filed May 26, 1928 Patented Aug. 6, 1929.

UNITED STATES LEONARD C. TINGLEY, OF PROVIDENCE,

PRODUCTS CORPORATION, CIF RHODE ISLAND.

I BHODE ISLAND, ASSIGHOR TO FEDERAL PROVIDENCE, RHODE ISLAND, A GUBEQRATIOIA" OF COVER PLATE F? MEAiiUBING INSTRUMENTS.

Application filed May 28, 1928. Serial No 280,815.

My present invention relates to measuring instrmnents, and more particularly to an improved cover plate for indicating or measuring instruments.

An in'iportant use vfor precision indicating instruments is the testing of completed parts with respect to the size thereof. For example, in building machine parts it is many times essential that no part is shipped from o a plant unless it is of a specified size. All

such parts are ordinarily allowed a certain minute variation from the specilied size, being allowed to be a certain measurement under the size or a certain measurement over the size, as for example, a part that is intended to be one inch in diameter will still be allowed to pass as a peritectarticle if it is, 1'01 example, three-thousandths of an inch under one inch in size, or, for example, twothousandths greater than one inch in size.

Precision indicating instruments as manufactured at the present day are utilized in this inspection work and are ordinarily provided with a dial. face over which moves a to rotatably mounted indicator hand and the dials of such precision measuring instruments may be graduated from a zero point either side thereof to indicate increase in size or decrease in size,'or, as it is usually known, plus or minus. \Vith the full face 01 the precision measuring instrument exposed, an operator who doing inspection work is seriously hampered in that there too great a scale over which close watch must be kept and the amount (it work turned out by an inspector is seriously all'ected by this -fact.

In my present invention, I have obviated the objections above enumerated and have devised an improved cover plate for precision measuring instruments which cover plate is provided with a plurality of movable shutters and by means of which as much of the graduated portion of either the plus or minus side of the device may be covered up. In this way, and it, as stated above, an article to be inspected is allowed to be three-thousandths under size and tWo-thousandths over size and still be within allowable limits or tolerances, then the movable members of the cover plate may be moved so that but three of the graduations on the minus side are exposed to view, while only two on the ins side are exposed. .An inspector, there ore,

inspecting articles with a precision measurnip; instrument, equipped with one of my im-' proved cover plates need only measure the article and ii the indicating hand of the ii'istrumcnt is visible, then the article n'ieasured is known to be correct within the allowable limits, whereas, it the indicating hand of the instrument is not visible, the inspector iinstantly knows that the instrument is too large or too small and as he is not concerned with other than the fact that the article must jects the article withoutturther consideration.

I ()ne of the objects of my invention, theretow, is an improved precision measuring :mstrument. I

Another object of my invention is an irnproved cover plate for use in connection with precision measuring instruments.

In the accompanying drawings,

Fig. 1 is a front elevation of a precision measuring instrument to which my invention has been applied;

Fig. 2 is a side elevation of the instrument shown in Fig. 1 with the cover plate therefor shown in section; I i

Fig. 3 is an elevation similar to Fig. 1 but with the movable portions of the cover plate be within certain limits, he re in adjusted position;

B 1g. llis a developu'ient of one of the movable elements of the cover plate;

Fig. 5 is a development of the other.of such movable elements, and.

Fig. (i is an elevation of cover plate.

' Referring to the drawings, designates a precision measuring instrument of a well known type provided with a side through which may be seen a circular dial ll, provided with gradmrt ions 12 about the periphery thereof, such gradations preferably and in the present instance reading from the zero point 13 to the right or left, those on the left being marked with a minus sign ll, and those on the right being marked with the plus sign 15. Also forming part of the precision measuring instrument and associated with the graduated dial 11 is a rotatabiy mounted indicating hand 16. The pre cision measuring instrument has extending from one end a limiting stop 17- rigidly attached to a movable plunger 18 extending from the opposite end, which plunger oper ates a train of gearing within-idle ca ing of the body of the the instrument to control the movement of the indicating hand 16. The distance between the outer one of the members 17 and 18 may be varied or may be a characteristic of the instrrunent and constitute the correct size of an article to be measured or inspected. It is obvious that if an operator utilizing the instrument above described and as illus trated in Fig. 1, is to measure an article for correctness of size that he will have to keep all of the graduations of the dial 11 under observation and each time read the number of graduations to the right or left of the zero mark 13 in order to determine whether or not the article he is inspecting comes within the limits allowed during the manufac ture. Thisis extremely fatiguing to the operator and results in materially slowing down his output of work.

In the drawings, I have shown a cover plate consisting of an annular split ring 19, formed of resilient material of any desired kind and having formed integral therewith a cover 20, such cover being provided with a semi-circular sight 21. Centrally located on the inner face of the cover 20 and attached to such cover by a rivet 22 or in any other suitable manner so as to be rotatable with respect to the cover 20 are one or more segmental shutters 23 and 2%. Each of the shutters 23 and 2& is provided with a radially extending operating finger 25, and the annular member 19 of spring material is provided with a plurality of slits 26 which allow the member 19 to firmly grip the bezel ring 27 of the measuring instrument 10. The segmental shutters 23 and 24, being assembled on the inner face of the cover 20, with the radially extending fingers thereof extending outward over beyond the limits of the annular ring 19 and being rotatable on the tubular rivet 22, it is obvious that such shutter may be rotated so as to expose more orless, as may be desired, of the graduations 11 to the right or left of the Zero mark 13.

If the device has been constructed as above described, and if we assume that it is desired to inspect a number of articles for size of an assumed length between the outer ends of the members 17 and 18, and that any article so inspected will be merchantable if it is, for example, three-thousandths less than such size, or two-thousandths over such size, then the operator by moving the shutter 2 to expose three of the minus graduations, to the left of the zero mark 13 and the shutter 24 to expose two of the plus graduations on the right of such zero graduation, then it is obvious that the operator will only have to watch the gradua-tions that are ex posed to view. In measuring an article, therefore, if the indicating hand 16 comes into view, whether to the right or to the left of the zero point 13, then the article measured is merchantable and passes inspection. On the contrary, if the indicating hand 16 does not come into view, it will be immaterial whether the article measured is too large or too small, it is summarily rejected. lVith this device, therefore, the inspector finds that his work is greatly speeded up and a great deal. more work may be done with less fatigue than is possible with former devices.

Having thus described my invention, what I claim as new isi 1 In a device of the kind described, the combination of an annular supporting ring, a cover formed on one edge thereof and being provided with a semi-circular sight, a pair of co-operating shutters pivotally 'mounted to said cover and movable to expose more or less of the sight.

2. In a device of the kind described, the combination of an annular spring ring, a cover formedintegral therewith at one edge thereof and being provided with a semi-circular sight, a pair of co-operating shutters rotatably mounted on the under face of the cover, operating fingers for said shutter plates and by means of which the shutter plates may be rotated to expose more or less of the semi-circular sight.

3. In a device of the kind described, the combination with a precision measuring instrument, having a graduated face, of a cover plate therefor comprising a spring ring adapted to engage with and be positioned on the bezel ring of the measuring instrument, a cover formed integral with the spring ring at one edge thereof and being provided with a semi-circular sight, a pair of co-operat-ing shutters rotatably mounted on the cover and means for operating the same to expose more or less of the grzuluations visible through the semi-circular sight.

In testimony whereof, I have signed my name to thisspecification.

LEONARD C. 'IINGLEY. 

